This invention relates to continuous casting machines and, more particularly, to a continuous casting machine provided with a cooling guide disposed immediately beneath the mould for the purpose of preventing break-out of the billet as it is withdrawn from the mould.
In the recent continuous casting machines, increase of the casting speed is called for in order to better the productivity. In order to realize high-speed casting, however, the billet has to be cooled down uniformly and quickly to form a thick shell capable of withstanding the high speed casting. In addition, it is necessary to provide means for preventing the rupture of the outer shell or so-called "break-out" with the inner mold flowing out through the broken shell. As one measure against this break-out, provision of the so-called cooling guide, which is a cooling jacket or the like disposed immediately beneath the mould and vertically oscillated in synchronism to the mould, has been adopted in place of spray cooling which has been the usual cooling method. For example, in a "high-speed cast billet support means" disclosed in the Japanese Unexamined Published Patent Application No. 40632/1973 a cooling jacket is urged against each side of the billet to cool the billet. This type of cooling guide, however, has its main aim in the cooling of the four flat sides of the billet, and the corners of the billet are cooled by merely jetting cooling water from water sprays. However, the inventors have found from their experience that the majority of break-outs take place at the corners of the billet immediately beneath the mould, so that the disclosed invention is set not much apart from the conventional spray cooling in so far as the prevention of break-out at the billet corner is concerned.